package priv.pront.code.mati.province;

import java.util.Scanner;

/**
 * @Description:
 * @Author: pront
 * @Time:2023-11-11 14:30
 */
// FIXME 错一个点
public class MC0112_白日梦I {

    static int n;
    static int[] a;
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        n = scanner.nextInt();
        a = new int[n];
        int max = Integer.MIN_VALUE;
        double ans = 1.00;
        a[0] = scanner.nextInt();
        for (int i = 1; i < n; i++) {
            max = Math.max(max, a[i - 1]);
            a[i] = scanner.nextInt();
            ans = Math.max(ans, (double) max / a[i]);
        }
        System.out.printf("%.2f", 10 * ans);
    }
}
